Power Consumption

Life is not as affordable as it used to be, and items such as gasoline, natural gas, and electricity all top the list of resources which have exploded in price over the past few years. Add to this the limit of non-renewable resources compared to current demands, and you can see that the prices are only going to get worse. Planet Earth is needs our help, and needs it badly. With forests becoming barren of vegetation and snow capped poles quickly turning brown, the technology industry has a new attitude towards suddenly becoming "green". I'll spare you the powerful marketing hype that I get from various manufacturers every day, and get right to the point: your computer hasn't been doing much to help save energy... at least up until now.

To measure isolated video card power consumption, Benchmark Reviews uses the Kill-A-Watt EZ (model P4460) power meter made by P3 International. A baseline test is taken without a video card installed inside our computer system, which is allowed to boot into Windows and rest idle at the login screen before power consumption is recorded. Once the baseline reading has been taken, the graphics card is installed and the system is again booted into Windows and left idle at the login screen. Our final loaded power consumption reading is taken with the video card running a stress test using FurMark. Below is a chart with the isolated video card power consumption (not system total) displayed in Watts for each specified test product:

Video Card Power Consumption by Benchmark Reviews

VGA Product Description

(sorted by combined total power)

Idle Power

Loaded Power

NVIDIA GeForce GTX 480 SLI Set

82 W

655 W

NVIDIA GeForce GTX 590 Reference Design

53 W

396 W

ATI Radeon HD 4870 X2 Reference Design

100 W

320 W

AMD Radeon HD 6990 Reference Design

46 W

350 W

NVIDIA GeForce GTX 295 Reference Design

74 W

302 W

ASUS GeForce GTX 480 Reference Design

39 W

315 W

ATI Radeon HD 5970 Reference Design

48 W

299 W

NVIDIA GeForce GTX 690 Reference Design

25 W

321 W

ATI Radeon HD 4850 CrossFireX Set

123 W

210 W

ATI Radeon HD 4890 Reference Design

65 W

268 W

AMD Radeon HD 7970 Reference Design

21 W

311 W

NVIDIA GeForce GTX 470 Reference Design

42 W

278 W

NVIDIA GeForce GTX 580 Reference Design

31 W

246 W

NVIDIA GeForce GTX 570 Reference Design

31 W

241 W

ATI Radeon HD 5870 Reference Design

25 W

240 W

ATI Radeon HD 6970 Reference Design

24 W

233 W

NVIDIA GeForce GTX 465 Reference Design

36 W

219 W

NVIDIA GeForce GTX 680 Reference Design

14 W

243 W

Sapphire Radeon HD 4850 X2 11139-00-40R

73 W

180 W

NVIDIA GeForce 9800 GX2 Reference Design

85 W

186 W

NVIDIA GeForce GTX 780 Reference Design

10 W

275 W

NVIDIA GeForce GTX 770 Reference Design

9 W

256 W

NVIDIA GeForce GTX 280 Reference Design

35 W

225 W

NVIDIA GeForce GTX 260 (216) Reference Design

42 W

203 W

ATI Radeon HD 4870 Reference Design

58 W

166 W

NVIDIA GeForce GTX 560 Ti Reference Design

17 W

199 W

NVIDIA GeForce GTX 460 Reference Design

18 W

167 W

AMD Radeon HD 6870 Reference Design

20 W

162 W

NVIDIA GeForce GTX 670 Reference Design

14 W

167 W

ATI Radeon HD 5850 Reference Design

24 W

157 W

NVIDIA GeForce GTX 650 Ti BOOST Reference Design

8 W

164 W

AMD Radeon HD 6850 Reference Design

20 W

139 W

NVIDIA GeForce 8800 GT Reference Design

31 W

133 W

ATI Radeon HD 4770 RV740 GDDR5 Reference Design

37 W

120 W

ATI Radeon HD 5770 Reference Design

16 W

122 W

NVIDIA GeForce GTS 450 Reference Design

22 W

115 W

NVIDIA GeForce GTX 650 Ti Reference Design

12 W

112 W

ATI Radeon HD 4670 Reference Design

9 W

70 W

* Results are accurate to within +/- 5W.

The Sapphire Radeon HD 4870 X2 is clearly no stranger to high power bills based on the fact that it tops our chart for power consumption under load. Even at idle, the Sapphire Radeon HD 4870 X2 video card 100251SR gulps the watts down at a faster pace than the GeForce 9800 GX2 and single 4870 under maximum power conditions. Regardless of consumption, the power requirements for the Radeon HD 4870 X2 consist of only two six-pin PCI-Express power connections to ensure that the twin RV770 receives enough juice to push out the frames in 3D mode. This may leave some middle-market enthusiasts and lower-end gamers in search of a new power supply force feed the Radeon HD 4870 X2 the power it needs.

Most enthusiasts make the mistake of associating a smaller die process with an improved power efficiency. Clearly, the downside to the 55 nm RV770 GPU is it's lack of energy efficient operation. Putting two together on the same PCB doesn't double the consumption of a single Radeon HD 4870, but it sure does try. The power consumption measured under full load doesn't match the performance, but it certainly matched heat output. The idle power draw is extremely high, which is uncommon since emphasis is usually placed on idle/standby mode efficiency and conservation.

Taken as a whole the idle stand-by power consumption is pretty unforgivable, especially since this the condition your equipment will be in the majority of the time. While loaded power consumption is the highest we've ever seen, the price paid to your utility company for gaming would be about the same with just about any other video card. Once upon a time, the computer and gaming consoles seemed like an inexpensive alternative to arcade gaming... but that was before energy costs soared through the roof.

Radeon 4870 X2 Heat Output

Normally I would go into great detail and illustrate where a video card heats up the integrated components with use of a non-contact IR thermometer. However Sapphire kept a short leash on the Radeon 4870 X2 they loaned me, and it was back on sent on its way to the next editor only two days after first receiving it. No worries... I did what I could.

The ambient room temperature was steady at exactly 19.0°C and the inner-case temperature hovered around 32°C. To begin my testing, I used ATITool v0.26 to record GPU temperatures at idle and again at high-power 3D mode.

At idle, the Sapphire Radeon HD 4870 X2 recorded an extremely warm 76°C. This temperature in and of itself was enough to raise concern, but then again I hadn't even begun to use 3D mode which asks for another 220W. Using a full 3D load for roughly twenty minutes, the Radeon HD 4870 X2 didn't waste any time heating up the room. At full load, the twin RV770's produced an operating temperature of 92°C; by far the hottest I have seen any graphics product get.

The GPU nearest the blower fan recorded a low 65°C under load as measured from the backside of the PCB, while the GPU nearest the exhaust rated 78°C. The exhaust vent registered 63°C, while the pin-shaped heatsink bar along the side reached up to 86°C. Hopefully the aftermarket cooling industry won't waste any time designing a better cooling solution for the Radeon HD 4870 X2, because ATI could use some help.

Please continue to the review conclusion in the next section, where I share my final thoughts on the RV770 graphics processor and give my opinion of the new Radeon HD 4800-series product offerings.